OvmfPkg/IntelTdx: Enable separate-fv in IntelTdx/IntelTdxX64.fdf

OvmfPkg/IntelTdx: Enable separate-fv in IntelTdx/IntelTdxX64.fdf

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=4152

In current DXE FV there are 100+ drivers. Some of the drivers are not
used in Td guest. (Such as USB support drivers, network related drivers,
etc).

From the security perspective if a driver is not used, we'd should prevent
it from being loaded / started. There are 2 benefits:
1. Reduce the attack surface
2. Improve the boot performance

So we separate DXEFV into 2 FVs: DXEFV and NCCFV. All the drivers which
are not needed by a Confidential Computing guest are moved from DXEFV
to NCCFV.

The following patch will find NCCFV for non-cc guest and build FVHob
so that NCCFV drivers can be loaded / started in DXE phase.

Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Min Xu <min.m.xu@intel.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>